CN104315995B - TOF depth camera three-dimensional coordinate calibration device and method based on virtual multi-cube standard target - Google Patents

Abstract

The invention relates to a TOF depth camera three-dimensional coordinate calibration device and method based on a virtual multi-cube standard target. The device comprises a three-dimensional motion horizontally-moving platform, a TOF depth camera, a cubical target and a background board. The calibration method includes the steps that three orthometric one-dimensional motion horizontally-moving platforms move repeatedly in the three-dimensional direction, the virtual multi-cube standard target of a complex shape and with multiple feature points is formed, the space position and the three-dimensional measured coordinates of a target angular point can be accurately obtained, and high-precision three-dimensional coordinate calibration of the TOF depth camera is achieved. By means of the TOF depth camera three-dimensional coordinate calibration device and method, target angular point feature recognition difficulty of the TOF depth camera and measurement errors each time are greatly reduced, three-dimensional measurement precision of the TOF depth camera is improved, the angular point position and the number of feature points of the virtual multi-cube standard target can be set flexibly, and full-process high-precision automatic calibration is achieved easily.

Description

Tof depth camera three-dimensional coordinate based on virtual many cubes standard target demarcates dress Put and method

Technical field

The invention belongs to optical metrology and calibration technique field, it is based on virtual many cubes standard target particularly to a kind of The caliberating device of no-raster laser three-D tof (time-of-flight) depth camera and method.

Background technology

Being increasingly modified and being lifted with optical measurement and computer vision technique, the development of advanced manufacturing technology and product The measurement demand of the three-dimensional appearance information to complex object surface for the variation of demand constantly increases, and promotes optical three-dimensional measurement skill Art constantly develops, it has also become one of optical metrology and the optical major domain of information and direction.

As optical three-dimensional measurement technology of new generation, tof depth camera can obtain the gray scale letter of extraterrestrial target in real time Breath and the corresponding depth information of each pixel, with tradition laser three-dimensional scanning imaging, binocular stereo vision and be based on structure The 3-D imaging system of light is compared, and tof depth camera has that real-time is good, certainty of measurement is moderate, small volume, lightweight etc. excellent Gesture, is applied to rapidly navigation and the field such as map building, space rover, industrial processes manufacture of mobile robot.

In order to eliminate the systematic error causing due to the discordance between space coordinates and measurement coordinate system, three-dimensional seat Mark demarcation is that tof depth camera carries out a vital step in high-precision optical three-dimensional measurement, mainly passes through acquisition standard The three dimensions characteristic parameter of object target, and then try to achieve tof depth camera three-dimensional measurement coordinate to the coordinate change of space coordinatess The relation of changing completes the demarcation of three-dimensional coordinate.Thus, the locus of the standard item of selection and the extracted with high accuracy of form parameter It is the important guarantee that tof depth camera carries out high precision three-dimensional measurement with identification, and the standard of tof depth camera calibration and usage Target should be full of whole visual field, just can obtain the three-dimensional coordinate calibration result at tof depth camera field of view center and edge, thus Create the various scaling methods to tof depth camera, mainly have a two categories below:

(1) the tof depth camera based on plane marker demarcates mode, such as using tessellated demarcation mode (1.zhengyou,zhang.a flexible new technique for camera calibration.technical Report msr-tr-98-71, microsoft research.1998.2. Li Xingdong, Chen Chao, Li Mantian, Sun Lining. flight Time Method three-dimensional camera is demarcated and error compensation. machinery and electronics .2013 (11): 37-40；3. Pan East China. time-of-flight method The mechanism of no-raster three-dimensional imaging video camera and characteristic research. Zhejiang University Ph.D. Dissertation .2010.04；4. patent " 201210021469.4 the three-dimensional registration method based on tof depth camera "；5.young min kim,derek chan, christian theobalt,sebastian thrun.design and calibration of a multi-view tof sensor fusion system.computer vision and pattern recognition workshops, 2008.cvprw’08.ieee computer society conference.june 23-28,2008.anchorage,ak； 6.stefan fuchs,gerd hirzinger.extrinsic and depth calibration of tof- cameras.computer vision and pattern recognition,2008.cvpr 2008.ieee conference.june 23-28,2008.anchorage,ak；7.sung-yeol kim,woon cho,andreas koschan,and mongi a.abidi.depth data calibration and enhancement of time-of- flight video-plus-depth camera.future of instrumentation international workshop(fiiw).november 7-8,2011.oak ridge,tn；8.marvin lindner,ingo schiller, andreas kolb,reinhard koch.time-of-flight sensor calibration for accurate range sensing.computer vision and image understanding.2010(114):1318-1328； 9.miles hansard,radu horaud,michel amat,georgios evangelidis.automatic detection of calibration grids in time-of-flight images.computer vision and Image understanding.2014 (121): 108-118) or using dot matrixes demarcation mode (1. Cai Hui. vision survey Camera calibration in amount is studied with three-dimensional rebuilding method. Harbin Institute of Technology master thesis .2013.07； 2.jiyoung jung,yekeun jeong,jaesik park,hyowon ha,james dokyoon kim,and in-so kweon.a novel 2.5d pattern for extrinsic calibration of tof and camera fusion system.2011ieee/rsj international conference on intelligent robots and systems.september 25-30,2011.san francisco,ca,usa；3.frederic garcia,djamila aouada,bruno mirbach,andottersten.real-time distance-dependent mapping for a hybrid tof multi-camera rig.ieee journal of selected topics in signal Processing, 2012.6 (5): 425-436), the chequered with black and white plane chessboard pattern that these methods are placed to multiple angles (or dot matrixes figure) is repeatedly shot, then calculate each corner location at tessellated Difference angles (or Each round dot center of dot matrixes), further according to the demarcation to tof depth camera for the space coordinate transformation relational implementation, the party Method stated accuracy is higher, and application is relatively broad, but times of collection is many, and data handling procedure is complicated, and multiple angle points are carried Error is taken directly to be accumulated in final calibration result, stated accuracy is difficult to improve further, and then directly affects tof depth The three-dimensional measurement precision of camera；

(2) the tof depth camera based on complex characteristic stereo marker demarcates mode, such as using having different depth feature Cubic block or the stereoscopic article such as multilayer steps as canonical measure object carry out the scaling method of tof depth camera (1.tsai, r.a versatile camera calibration technique for high-accuracy 3d machine vision metrology using off-the-shelf tv cameras and lenses.ieee journal of robotics and automation.1987.ra-3(4):323-344；2. Xu De, Tan Min, Li Yuan. robot vision measures With control. National Defense Industry Press .2011.05；3.filiberto chiabrando,roberto chiabrando,dario piatti,fulvio rinaudo.sensors for 3d imaging:metric evaluation and calibration of a ccd/cmos time-of-flight camera.sensors.2009(9):10080-10096； 4.stuart robson,j.-angelo beraldin,andrew brownhill and lindsay macdonald.artefacts for optical surface measurement.proc.of spie vol.8085, videometrics,range imaging,and applications xi,80850c.may23,2011.munich, germany；5. patent 201210352365.1 " method for three-dimensional measurement demarcated based on computer vision cube "), these sides Although method can directly collect the different depth information of various location in complex characteristic object plane type, and then resolving obtains The measurement error of tof depth camera compensates, but the complex characteristic collecting is extracted due to needing simultaneously and know , not computationally intensive and extract error will accumulate in final calibration result, the three-dimensional coordinate stated accuracy of tof depth camera and Three-dimensional measurement precision is also difficult to improve further.

By above analysis as can be seen that in actual applications, the scaling method of tof depth camera widely used at present is equal There is following weak point: the target characteristic quantity that tof depth camera occurs in visual field in single acquisition more so that number Long according to processing procedure, target recognition and feature extraction complexity are high, thus directly results in the survey of target recognition and feature extraction Amount error accumulation enters in the three-dimensional coordinate calibration result of tof three-dimensional camera, largely effects on tof depth camera calibration result Accuracy and repeatability, thus limiting the range of application of tof depth camera, this is the existing scaling scheme deficiency of itself at present Part, is also current tof depth camera unsolved major issue in actual applications.

Content of the invention

It is an object of the invention to overcoming not enough present in above-mentioned existing tof depth camera scaling scheme, provide one Plant the tof depth camera three-dimensional coordinate caliberating device based on virtual many cubes standard target and method, this caliberating device includes Three-dimensional motion translation stage, tof depth camera, cubic objects and background board；This scaling method utilizes mutually orthogonal three Three orthogonal directions of x, y, z are made motion by motion in one dimension translation stage.By motion mode reasonable in design, each motion bit Put the single cubic objects combination in place tof depth camera visual field, constitute a void with complicated shape and multi-characteristic points Intend many cubes standard target, obtain the three-dimensional space position of Corner Feature of this target and measurement coordinate can try to achieve three-dimensional seat The coordinate conversion relation that mark is demarcated, realizes the three-dimensional coordinate to tof depth camera and demarcates.The present invention greatly reduces single tof Depth camera is demarcated to the difficulty of Corner feature identification and measurement error, the three-dimensional coordinate effectively improving tof depth camera And certainty of measurement, and the cubical corner location of virtual criterion and feature point number can be flexibly set, and it is easily achieved mistake entirely Process automation is demarcated.

The technical solution that the present invention adopts is: a kind of tof depth camera based on virtual many cubes standard target Three-dimensional coordinate caliberating device, including three-dimensional motion translation stage, tof depth camera, cubic objects and background board.Wherein, three The connected mode that maintenance and operation moves translation stage is that three motion in one dimension translation stages combine connection in three-dimensional pairwise orthogonal；Tof depth Camera is fixed on motion translation platform, carries out three-dimensional motion with three-dimensional motion translation stage；Background board is surface plate, with tof The optical axis of depth camera is vertical, and cubic objects are fixed on background board；Produced on three-dimensional using three-dimensional motion translation stage Motion several times, constitute virtual many cubes standard target with complicated shape and multi-characteristic points.

Present invention also offers a kind of tof depth camera three-dimensional coordinate demarcation side based on virtual many cubes standard target Method, the method comprises the following steps:

(1) determine tof depth camera coordinate system oxyz first, three translation shafts of D translation platform are defined as x, y, z three Individual direction, zero o orientates tof depth camera optical center as, and three-dimensional motion translation stage is installed bottom surface and is defined as xz plane, Parallel with tof depth camera installation bottom surface；Z direction is tof depth camera optical axis direction, with the motion of z direction translation stage translation shaft Direction is parallel；The vertical direction of bottom surface is installed for three-dimensional motion translation stage in y direction；The direction that x direction defines for right-handed coordinate system； The following institute of three-dimensional coordinate transformational relation between space coordinates oxyz and tof depth camera three-dimensional measurement coordinate system ocxcyczc Show:

$\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ 1\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{nx}}_x& {\mathrm{ny}}_x& {\mathrm{nz}}_x& p_x\\ {\mathrm{nx}}_y& {\mathrm{ny}}_y& {\mathrm{nz}}_y& p_y\\ {\mathrm{nx}}_z& {\mathrm{ny}}_z& {\mathrm{nz}}_z& p_z\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_w\\ y_w\\ z_w\\ 1\end{array}\right]$

Wherein, x_c, y_c, z_cRepresent seat under tof depth camera three-dimensional measurement coordinate system for any point on cubic objects Mark, x_w, y_w, z_wRepresent this coordinate under space coordinates oxyz, nx_x, nx_y, nx_zRepresentation space coordinate system x-axis is deep in tof Direction vector under degree camera three-dimensional measurement coordinate system, ny_x, ny_y, ny_zRepresentation space coordinate system y-axis is three-dimensional in tof depth camera Direction vector under measurement coordinate system, nz_x, nz_y, nz_zRepresentation space coordinate system z-axis is in tof depth camera three-dimensional measurement coordinate system Under direction vector, p_x, p_y, p_zSeat under tof depth camera three-dimensional measurement coordinate system for the zero of representation space coordinate system Mark；

(2) initial position of adjustment tof depth camera and cubic objects is so that cubic objects end face and tof depth Camera lens surface is close to, and ensures that tof depth camera camera lens optical axis pass through cubic objects center；

(3) control z direction motion translation platform to drive tof depth camera movable in the z-direction, produce z direction precise displacement, Reach at z orientation determining location sz, the motion of z direction completes；

(4) control x direction motion translation platform and y direction motion translation platform, drive tof depth camera at sz position, Carry out coverage motion in x/y plane, form virtual many cubes standard target；At each position in moving in x/y plane, stand Four angle point locus coordinates of cube target top surface can be by the length and width of cubic objects and motion translation platform Movement position uniquely determine, be shown below:

$\left\{\begin{array}{c}\mathrm{pij}1(\mathrm{xij}1,\mathrm{yij}1,\mathrm{zij}1)=\mathrm{pij}1(\mathrm{sxij}+l/2,\mathrm{syij}+w/2,\mathrm{sz})\\ \mathrm{pij}2(\mathrm{xij}2,\mathrm{yij}2,\mathrm{zij}2)=\mathrm{pij}2(\mathrm{sxij}-l/2,\mathrm{syij}+w/2,\mathrm{sz})\\ \mathrm{pij}3(\mathrm{xij}3,\mathrm{yij}3,\mathrm{zij}3)=\mathrm{pij}3(\mathrm{sxij}-l/2,\mathrm{syij}-w/2,\mathrm{sz})\\ \mathrm{pij}4(\mathrm{xij}4,\mathrm{yij}4,\mathrm{zij}4)=\mathrm{pij}4(\mathrm{sxij}+l/2,\mathrm{syij}-w/2,\mathrm{sz})\end{array}\right.$

Wherein, i (i=1,2,3 ... ...) and j (j=1,2,3 ... ...) is respectively tof depth camera x side in x/y plane To the position number moving with y direction；pij1(xij1,yij1,zij1)、pij2(xij2,yij2,zij2)、pij3(xij3, Yij3, zij3), pij4 (xij4, yij4, zij4) be respectively cubic objects top surface four angle points in space coordinates oxyz Under locus coordinate；The precise displacement that sxij moves in x direction for x direction motion translation platform；Syij is flat for the motion of y direction The precise displacement that moving stage is moved in y direction；The precise displacement that sz moves in z direction for z direction motion translation platform；L and w is respectively The length and width of cubic objects.

(5) tof depth camera carries out three-dimensional measurement to cubic objects, obtains four angle point positions of cubic objects top surface The three-dimensional measurement coordinate figure put it may be assumed that four angle points coordinate under tof depth camera three-dimensional measurement coordinate system ocxcyczc respectively For: pij1 ' (xij1 ', yij1 ', zij1 '), pij2 ' (xij2 ', yij2 ', zij2 '), pij3 ' (xij3 ', yij3 ', zij3’)、pij4’(xij4’,yij4’,zij4’)；

(6) travel through whole x/y plane, obtain the space of cubic objects angle point at all of xy position at this z direction position Position and three-dimensional coordinate measurement value.Bring in above-mentioned three-dimensional coordinate transformational relation, solution system of linear equations can achieve to tof depth The demarcation of the three-dimensional coordinate of camera.

The invention has the characteristics that and good result:

(1) present invention makes full use of three mutually orthogonal axle high-precision motion translation stages and produces on three-dimensional several times Motion, the simple target in tof depth camera visual field at each movement position combines, and constitutes and has complicated shape and feature Point virtual many cubes standard target, this be different from existing tof depth camera three-dimensional coordinate calibration technique innovative point it One；

(2) in the present invention, in tof depth camera visual field at each movement position, only have a target, and background be simple, So that each tof depth camera to target recognition and the data handling procedure extracted is simple, it is possible to achieve simple target accurate Corner Feature extract and identify, greatly reduce target's feature-extraction identification difficulty and identification error, this be different from existing The two of the innovative point of tof depth camera calibration technique；

(3) present invention passes through the three-dimensional motion using mutually orthogonal three-dimensional high-precision motion translation platform, constructs one The standard target with complicated shape and multi-characteristic points of virtual many cube compositions, in the different positions of tof depth camera visual field Put, obtain the three-dimensional space position of three-dimensional measuring result and target, such that it is able to calculate the three-dimensional coordinate completing tof depth camera Demarcate, meet the demand of tof depth camera three-dimensional coordinate demarcation, reduce complex target feature identification error, improve tof The three-dimensional coordinate stated accuracy of depth camera, reduces due to space coordinates and the not corresponding system introducing of measurement coordinate system by mistake Difference, and then improve the three-dimensional measurement precision of tof depth camera, and measurement process data process all substantially simplify it is easy to Realize whole-course automation to demarcate, practical.

Brief description

Fig. 1 is the structural representation of apparatus of the present invention；

Fig. 2 is the structural representation of mutually orthogonal three-dimensional motion translation stage in apparatus of the present invention and its tof depth camera；

Fig. 3 is the schematic diagram that during motion translation platform 3 × 3 motion in the present invention, target is imaged in tof depth camera visual field；

Fig. 4 be in the present invention motion translation platform 3 × 3 motion after constitute virtual many cubes standard target structural representation Figure；

Fig. 5 is locus coordinate schematic diagram in x/y plane for the virtual many cubes standard target angle point in the present invention.

Specific embodiment

With reference to figure and embodiment, to the present invention, the tof depth camera based on virtual many cubes standard target is demarcated Apparatus and method are described in detail:

As shown in figure 1, assembly of the invention is by z direction motion translation platform 1, x direction motion translation platform 2, the motion of y direction is flat Moving stage 3, tof depth camera 4, cubic objects 5 and background board 6 etc. are constituted.Wherein: as shown in Fig. 2 x direction motion translation The connected mode of platform 2, y direction motion translation platform 3 and z direction motion translation platform 1 is that space three-dimensional direction pairwise orthogonal connects, z The direction of motion of direction motion translation platform 1 is parallel with the optical axis direction of tof depth camera 4, and tof depth camera 4 is fixed on y direction On motion translation platform 3, the installation bottom surface of tof depth camera 4 is parallel with z direction motion translation platform installation bottom surface, tof depth camera 4 carry out three-dimensional motion with three motion translation platforms；Background board 6 is surface plate, vertical with the optical axis of tof depth camera 4, stands Cube target 5 is fixed on background board 6.

The following detailed description of method of the present invention:

(1) determine tof depth camera 4 coordinate system oxyz first, three translation shafts of D translation platform are defined as x, y, z three Individual direction, zero o orientates the optical center of tof depth camera 4 as, and three-dimensional motion translation stage installation bottom surface is defined as xz and puts down Face, parallel with tof depth camera 4 installation bottom surface；Z direction is tof depth camera 4 optical axis direction, translates with z direction translation stage 1 The axle direction of motion is parallel；The vertical direction of bottom surface is installed for three-dimensional motion translation stage in y direction；X direction defines for right-handed coordinate system Direction；Three-dimensional coordinate conversion between space coordinates oxyz and tof depth camera 4 three-dimensional measurement coordinate system ocxcyczc is closed It is as follows:

$\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ 1\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{nx}}_x& {\mathrm{ny}}_x& {\mathrm{nz}}_x& p_x\\ {\mathrm{nx}}_y& {\mathrm{ny}}_y& {\mathrm{nz}}_y& p_y\\ {\mathrm{nx}}_z& {\mathrm{ny}}_z& {\mathrm{nz}}_z& p_z\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_w\\ y_w\\ z_w\\ 1\end{array}\right]$

Wherein, x_c, y_c, z_cRepresent that on cubic objects 5, any point is under tof depth camera 4 three-dimensional measurement coordinate system Coordinate, x_w, y_w, z_wRepresent this coordinate under space coordinates oxyz, nx_x, nx_y, nx_zRepresentation space coordinate system x-axis is in tof Direction vector under depth camera 4 three-dimensional measurement coordinate system, ny_x, ny_y, ny_zRepresentation space coordinate system y-axis is in tof depth camera 4 Direction vector under three-dimensional measurement coordinate system, nz_x, nz_y, nz_zRepresentation space coordinate system z-axis is in tof depth camera 4 three-dimensional measurement Direction vector under coordinate system, p_x, p_y, p_zThe zero of representation space coordinate system is in tof depth camera 4 three-dimensional measurement coordinate Coordinate under system；

(2) initial position of adjustment tof depth camera 4 and cubic objects 5 is so that the end face of cubic objects 5 and tof The camera lens surface of depth camera 4 is close to, and ensures the camera lens optical axis of tof depth camera 4 by cubic objects center；

(3) control z direction motion translation platform 1 to drive tof depth camera 4 movable in the z-direction, produce the accurate position in z direction Move, reach at z orientation determining location sz, the motion of z direction completes；

(4) control x direction motion translation platform 2 and y direction motion translation platform 3, drive tof depth camera 4 at sz position, Carry out coverage motion and form virtual many cubes standard target in x/y plane；At each position in moving in x/y plane, Four corner location coordinates of cubic objects 5 top surface can be flat by the length and width of cubic objects 5 and three motions The movement position of moving stage uniquely determines, is shown below:

$\left\{\begin{array}{c}\mathrm{pij}1(\mathrm{xij}1,\mathrm{yij}1,\mathrm{zij}1)=\mathrm{pij}1(\mathrm{sxij}+l/2,\mathrm{syij}+w/2,\mathrm{sz})\\ \mathrm{pij}2(\mathrm{xij}2,\mathrm{yij}2,\mathrm{zij}2)=\mathrm{pij}2(\mathrm{sxij}-l/2,\mathrm{syij}+w/2,\mathrm{sz})\\ \mathrm{pij}3(\mathrm{xij}3,\mathrm{yij}3,\mathrm{zij}3)=\mathrm{pij}3(\mathrm{sxij}-l/2,\mathrm{syij}-w/2,\mathrm{sz})\\ \mathrm{pij}4(\mathrm{xij}4,\mathrm{yij}4,\mathrm{zij}4)=\mathrm{pij}4(\mathrm{sxij}+l/2,\mathrm{syij}-w/2,\mathrm{sz})\end{array}\right.$

Wherein, i (i=1,2,3 ... ...) and j (j=1,2,3 ... ...) is respectively tof depth camera 4 x in x/y plane Direction and the position number of y direction motion；pij1(xij1,yij1,zij1)、pij2(xij2,yij2,zij2)、pij3 Four angle points that (xij3, yij3, zij3), pij4 (xij4, yij4, zij4) are respectively cubic objects 5 top surface are sat in space Coordinate under mark system oxyz；The precise displacement that sxij moves in x direction for x direction motion translation platform 2；Syij moves for y direction The precise displacement that translation stage 3 moves in y direction；The precise displacement that sz moves in z direction for z direction motion translation platform 1；L and w divides Not Wei cubic objects 5 length and width.

(5) tof depth camera 4 carries out three-dimensional measurement to cubic objects 5, obtains four angles of cubic objects 5 top surface The three-dimensional measurement coordinate figure of point position is it may be assumed that four angle points seat under tof depth camera 4 three-dimensional measurement coordinate system ocxcyczc Mark be respectively as follows: pij1 ' (xij1 ', yij1 ', zij1 '), pij2 ' (xij2 ', yij2 ', zij2 '), pij3 ' (xij3 ', yij3 ', zij3’)、pij4’(xij4’,yij4’,zij4’)；

(6) travel through whole x/y plane, obtain cubic objects 5 angle point at all of xy position at now z direction position Locus and three-dimensional measurement coordinate figure, bring in above-mentioned coordinate transformation relation, and solution system of linear equations can achieve to tof depth The three-dimensional coordinate of camera 4 is demarcated, and completes whole calibration process.

It can be seen that, by the three-dimensional motion using three mutually orthogonal axle high-precision motion translation stages, construct one virtual The standard target with complicated shape and multi-characteristic points of many cube compositions, in the diverse location of tof depth camera 4 visual field, Obtain the accurate three-dimensional locus of three-dimensional measuring result and target, demarcate thus calculating and completing three-dimensional coordinate, meet tof deep The demand that degree camera 4 three-dimensional coordinate is demarcated, reduces complex target feature identification error, improves the three-dimensional of tof depth camera 4 Coordinate stated accuracy, and measurement process data processes and all substantially simplifies, it is easy to accomplish and whole-course automation is demarcated, practicality By force.

Embodiment 1:

(1) with tof depth camera 4 at 0.5m distance and position, x direction motion translation platform 2 and y direction motion translation platform 3 As a example combination carries out 3 × 3 motions in x/y plane, the caliberating device and the method that describe present invention introduction in detail are as follows:

As shown in Figure 1, it is first determined tof depth camera 4 coordinate system oxyz, three translation shafts of D translation platform are defined as Three directions of x, y, z, zero o orientates the optical center of tof depth camera 4 as, and it is fixed that three-dimensional motion translation stage installs bottom surface Justice is xz plane, parallel with tof depth camera 4 installation bottom surface；Z direction is tof depth camera 4 optical axis direction, with the translation of z direction The platform 1 translation shaft direction of motion is parallel；The vertical direction of bottom surface is installed for three-dimensional motion translation stage in y direction；X direction is right-handed scale (R.H.scale) The direction of system's definition；Three-dimensional coordinate between space coordinates oxyz and tof depth camera 4 three-dimensional measurement coordinate system ocxcyczc Transformational relation is as follows:

$\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ 1\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{nx}}_x& {\mathrm{ny}}_x& {\mathrm{nz}}_x& p_x\\ {\mathrm{nx}}_y& {\mathrm{ny}}_y& {\mathrm{nz}}_y& p_y\\ {\mathrm{nx}}_z& {\mathrm{ny}}_z& {\mathrm{nz}}_z& p_z\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_w\\ y_w\\ z_w\\ 1\end{array}\right]$

Wherein, x_c, y_c, z_cRepresent that on cubic objects 5, any point is under tof depth camera 4 three-dimensional measurement coordinate system Coordinate, x_w, y_w, z_wRepresent this coordinate under space coordinates oxyz, nx_x, nx_y, nx_zRepresentation space coordinate system x-axis is in tof Direction vector under depth camera 4 three-dimensional measurement coordinate system, ny_x, ny_y, ny_zRepresentation space coordinate system y-axis is in tof depth camera 4 Direction vector under three-dimensional measurement coordinate system, nz_x, nz_y, nz_zRepresentation space coordinate system z-axis is in tof depth camera 4 three-dimensional measurement Direction vector under coordinate system, p_x, p_y, p_zThe zero of representation space coordinate system is in tof depth camera 4 three-dimensional measurement coordinate Coordinate under system；

(2) initial position of adjustment tof depth camera 4 and cubic objects 5 is so that the end face of cubic objects 5 and tof The camera lens surface of depth camera 4 is close to, and ensures the camera lens optical axis of tof depth camera 4 by cubic objects center；

(3) control z direction motion translation platform 1 to drive tof depth camera 4 movable in the z-direction, produce the accurate position in z direction Move, reach at z orientation determining location sz=0.5m position, the motion of z direction completes；

(4) control x direction motion translation platform 2 and y direction motion translation platform 3, drive tof depth camera 4 at sz position, Carry out coverage motion in x/y plane, the top surface of cubic objects 5 imaging schematic diagram in tof depth camera 4 visual field during motion As shown in figure 3, forming virtual many cubes standard target schematic diagram as shown in figure 4, producing the accurate benchmark displacement of x and y direction；? At each position in motion in x/y plane, four corner location coordinates of cubic objects 5 top surface can be by cubic objects 5 Length and width and the movement position of three motion translation platforms uniquely determine, virtual many cubes standard target angle point is in xy Locus coordinate schematic diagram in plane is as shown in figure 5, be shown below:

$\left\{\begin{array}{c}\mathrm{pij}1(\mathrm{xij}1,\mathrm{yij}1,\mathrm{zij}1)=\mathrm{pij}1(\mathrm{sxij}+l/2,\mathrm{syij}+w/2,\mathrm{sz})\\ \mathrm{pij}2(\mathrm{xij}2,\mathrm{yij}2,\mathrm{zij}2)=\mathrm{pij}2(\mathrm{sxij}-l/2,\mathrm{syij}+w/2,\mathrm{sz})\\ \mathrm{pij}3(\mathrm{xij}3,\mathrm{yij}3,\mathrm{zij}3)=\mathrm{pij}3(\mathrm{sxij}-l/2,\mathrm{syij}-w/2,\mathrm{sz})\\ \mathrm{pij}4(\mathrm{xij}4,\mathrm{yij}4,\mathrm{zij}4)=\mathrm{pij}4(\mathrm{sxij}+l/2,\mathrm{syij}-w/2,\mathrm{sz})\end{array}\right.$

Wherein, i (i=1,2,3 ... ...) and j (j=1,2,3 ... ...) is respectively tof depth camera 4 x in x/y plane Direction and the position number of y direction motion；pij1(xij1,yij1,zij1)、pij2(xij2,yij2,zij2)、pij3 Four angle points that (xij3, yij3, zij3), pij4 (xij4, yij4, zij4) are respectively cubic objects 5 top surface are sat in space Coordinate under mark system oxyz；The precise displacement that sxij moves in x direction for x direction motion translation platform 2；Syij moves for y direction The precise displacement that translation stage 3 moves in y direction；The precise displacement that sz moves in z direction for z direction motion translation platform 1；L and w divides Not Wei cubic objects 5 length and width.

(5) tof depth camera 4 carries out three-dimensional measurement to cubic objects 5, obtains four angles of cubic objects 5 top surface The three-dimensional measurement coordinate figure of point position is it may be assumed that four angle points seat under tof depth camera 4 three-dimensional measurement coordinate system ocxcyczc Mark be respectively as follows: pij1 ' (xij1 ', yij1 ', zij1 '), pij2 ' (xij2 ', yij2 ', zij2 '), pij3 ' (xij3 ', yij3 ', zij3’)、pij4’(xij4’,yij4’,zij4’)；

(6) travel through whole x/y plane, obtain the space amounting to 36 angle points of cubic objects 5 at now z direction position Position and three-dimensional measurement coordinate figure, bring in above-mentioned coordinate transformation relation, and solution system of linear equations can achieve to tof depth camera 4 three-dimensional coordinate is demarcated, and completes whole calibration process.

In the present embodiment, x direction motion translation platform 2, y direction motion translation platform 3 and z direction motion translation platform 1 all adopt High precision electric control translation stage, positioning precision is superior to 0.05mm, and wherein, x direction motion translation platform 2 stroke is better than 2m, and y direction is transported Dynamic translation stage 3 stroke is better than 1m, and z direction motion translation platform 1 stroke is better than 0.4m；Tof depth camera 4 three-dimensional measurement distance is 0.5m～5m, three-dimensional measurement precision is ± 10mm, and cubic objects 5 are the square target of length of side 150mm.Due to automatically controlled translation The positioning precision of platform is significantly larger than the certainty of measurement of tof depth camera 4, and the therefore position error of motion translation platform itself can be neglected Slightly.Calibration experiment result shows, whole measurement process achieves whole-course automation, and the scaling method providing using the present invention The certainty of measurement of calibrated tof depth camera by ± 10mm brought up to better than 6.85mm it is achieved that tof depth camera from Dynamicization high-precision three-dimensional is demarcated.

Embodiment 2:

As shown in figure 1, the rectangular shape that cubic objects 5 are not completely equivalent for length, width and height, other portions of the present embodiment Part and operation principle are all same as Example 1.

There is provided above example to be used for the purpose of the description purpose of the present invention, and be not intended to limit the scope of the present invention.This The scope of invention is defined by the following claims.Various equivalents made without departing from spirit and principles of the present invention and repairing Change, all should cover within the scope of the present invention.

Claims (6)

1. a kind of tof depth camera three-dimensional coordinate caliberating device based on virtual many cubes standard target, including three-dimensional motion Translation stage, tof depth camera, cubic objects and background board it is characterised in that: the connection side of described three-dimensional motion translation stage Formula is that three motion in one dimension translation stages combine connection in three-dimensional pairwise orthogonal, and tof depth camera is fixed on three-dimensional motion and puts down In moving stage, carry out three-dimensional motion with three-dimensional motion translation stage, background board is surface plate, hang down with the optical axis of tof depth camera Directly, cubic objects are fixed on background board；Produce the motion several times on three-dimensional using three-dimensional motion translation stage, constitute One virtual many cubes standard target with complicated shape and multi-characteristic points；Calibration process is as follows:

(1) determine tof depth camera coordinate system oxyz first, three translation shafts of D translation platform are defined as three sides of x, y, z To, zero o orientates tof depth camera optical center as, and three-dimensional motion translation stage is installed bottom surface and is defined as xz plane, with It is parallel that tof depth camera installs bottom surface；Z direction is tof depth camera optical axis direction, with z direction translation stage translation shaft motion side To parallel；The vertical direction of bottom surface is installed for three-dimensional motion translation stage in y direction；The direction that x direction defines for right-handed coordinate system；Empty Between the following institute of three-dimensional coordinate transformational relation between coordinate system oxyz and tof depth camera three-dimensional measurement coordinate system ocxcyczc Show:

$\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ 1\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{nx}}_x& {\mathrm{ny}}_x& {\mathrm{nz}}_x& p_x\\ {\mathrm{nx}}_y& {\mathrm{ny}}_y& {\mathrm{nz}}_y& p_y\\ {\mathrm{nx}}_z& {\mathrm{ny}}_z& {\mathrm{nz}}_z& p_z\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_w\\ y_w\\ z_w\\ 1\end{array}\right]$

Wherein, x_c, y_c, z_cRepresent coordinate under tof depth camera three-dimensional measurement coordinate system for any point on cubic objects, x_w, y_w, z_wRepresent this coordinate under space coordinates oxyz, nx_x, nx_y, nx_zRepresentation space coordinate system x-axis is in tof depth Direction vector under camera three-dimensional measurement coordinate system, ny_x, ny_y, ny_zRepresentation space coordinate system y-axis is in the three-dimensional survey of tof depth camera Direction vector under amount coordinate system, nz_x, nz_y, nz_zRepresentation space coordinate system z-axis is under tof depth camera three-dimensional measurement coordinate system Direction vector, p_x, p_y, p_zSeat under tof depth camera three-dimensional measurement coordinate system for the zero of representation space coordinate system Mark；

(2) initial position of adjustment tof depth camera and cubic objects is so that cubic objects end face and tof depth camera Camera lens surface is close to, and ensures that tof depth camera camera lens optical axis pass through cubic objects center；

(3) control z direction motion translation platform to drive tof depth camera movable in the z-direction, produce z direction precise displacement, reach At z orientation determining location sz, the motion of z direction completes；

(4) control x direction motion translation platform and y direction motion translation platform, drive tof depth camera at sz position, put down in xy Carry out coverage motion in face, form virtual many cubes standard target；At each position in moving in x/y plane, cube Four feature angle point position coordinateses of target top surface can be by the fortune of the length and width of cubic objects and motion translation platform Dynamic position uniquely determines, is shown below:

$\left\{\begin{array}{c}pij1(xij1,yij1,zij1)=pij1(sxij+l/2,syij+w/2,sz)\\ pij2(xij2,yij2,zij2)=pij2(sxij-l/2,syij+w/2,sz)\\ pij3(xij3,yij3,zij3)=pij3(sxij-l/2,syij-w/2,sz)\\ pij4(xij4,yij4,zij4)=pij4(sxij+l/2,syij-w/2,sz)\end{array}\right.$

Wherein, the position number of i and j respectively tof depth camera x direction and the motion of y direction in x/y plane, i=1,2, 3 ... ..., j=1,2,3 ... ...；pij1(xij1,yij1,zij1)、pij2(xij2,yij2,zij2)、pij3(xij3, Yij3, zij3), pij4 (xij4, yij4, zij4) be respectively cubic objects top surface four angle points in space coordinates oxyz Under coordinate；The precise displacement that sxij moves in x direction for x direction motion translation platform；Syij is y direction motion translation platform in y The precise displacement of direction motion；The precise displacement that sz moves in z direction for z direction motion translation platform；L and w is respectively cube The length and width of target；

(5) tof depth camera carries out three-dimensional measurement to cubic objects, obtains four corner location of cubic objects top surface Three-dimensional measurement coordinate figure is it may be assumed that four angle points coordinate under tof depth camera three-dimensional measurement coordinate system ocxcyczc is respectively as follows: pij1’(xij1’,yij1’,zij1’)、pij2’(xij2’,yij2’,zij2’)、pij3’(xij3’,yij3’,zij3’)、 pij4’(xij4’,yij4’,zij4’)；

(6) travel through whole x/y plane, obtain the locus of cubic objects angle point at all of xy position at this z direction position With three-dimensional coordinate measurement value, bring in above-mentioned three-dimensional coordinate transformational relation, solution system of linear equations is realized to tof depth camera The demarcation of three-dimensional coordinate.

2. device according to claim 1 it is characterised in that: the cube number of described virtual many cubes standard target And cubic site is determined by the three-dimensional motion combination of three-dimensional motion translation stage.

3. device according to claim 1 it is characterised in that: described three-dimensional motion translation stage adopt electronic control translation stage realize Three-dimensional motion.

4. device according to claim 1 it is characterised in that: described cubic objects are the equal square mesh of the length of side Mark.

5. device according to claim 1 it is characterised in that: described cubic objects are the length that length, width and height are not completely equivalent Cube target.

6. a kind of tof depth camera three-dimensional coordinate scaling method based on virtual many cubes standard target is it is characterised in that institute The scaling method stated comprises the following steps:

(1) determine tof depth camera coordinate system oxyz first, three translation shafts of D translation platform are defined as three sides of x, y, z To, zero o orientates tof depth camera optical center as, and three-dimensional motion translation stage is installed bottom surface and is defined as xz plane, with It is parallel that tof depth camera installs bottom surface；Z direction is tof depth camera optical axis direction, with z direction translation stage translation shaft motion side To parallel；The vertical direction of bottom surface is installed for three-dimensional motion translation stage in y direction；The direction that x direction defines for right-handed coordinate system；Empty Between the following institute of three-dimensional coordinate transformational relation between coordinate system oxyz and tof depth camera three-dimensional measurement coordinate system ocxcyczc Show:

$\left[\begin{array}{c}{x}_c\\ y_c\\ z_c\\ 1\end{array}\right]=\left[\begin{array}{cccc}{\mathrm{nx}}_x& {\mathrm{ny}}_x& {\mathrm{nz}}_x& p_x\\ {\mathrm{nx}}_y& {\mathrm{ny}}_y& {\mathrm{nz}}_y& p_y\\ {\mathrm{nx}}_z& {\mathrm{ny}}_z& {\mathrm{nz}}_z& p_z\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{c}{x}_w\\ y_w\\ z_w\\ 1\end{array}\right]$

Wherein, x_c, y_c, z_cRepresent coordinate under tof depth camera three-dimensional measurement coordinate system for any point on cubic objects, x_w, y_w, z_wRepresent this coordinate under space coordinates oxyz, nx_x, nx_y, nx_zRepresentation space coordinate system x-axis is in tof depth Direction vector under camera three-dimensional measurement coordinate system, ny_x, ny_y, ny_zRepresentation space coordinate system y-axis is in the three-dimensional survey of tof depth camera Direction vector under amount coordinate system, nz_x, nz_y, nz_zRepresentation space coordinate system z-axis is under tof depth camera three-dimensional measurement coordinate system Direction vector, p_x, p_y, p_zSeat under tof depth camera three-dimensional measurement coordinate system for the zero of representation space coordinate system Mark；

(2) initial position of adjustment tof depth camera and cubic objects is so that cubic objects end face and tof depth camera Camera lens surface is close to, and ensures that tof depth camera camera lens optical axis pass through cubic objects center；

(3) control z direction motion translation platform to drive tof depth camera movable in the z-direction, produce z direction precise displacement, reach At z orientation determining location sz, the motion of z direction completes；

(4) control x direction motion translation platform and y direction motion translation platform, drive tof depth camera at sz position, put down in xy Carry out coverage motion in face, form virtual many cubes standard target；At each position in moving in x/y plane, cube Four feature angle point position coordinateses of target top surface can be by the fortune of the length and width of cubic objects and motion translation platform Dynamic position uniquely determines, is shown below:

$\left\{\begin{array}{c}pij1(xij1,yij1,zij1)=pij1(sxij+l/2,syij+w/2,sz)\\ pij2(xij2,yij2,zij2)=pij2(sxij-l/2,syij+w/2,sz)\\ pij3(xij3,yij3,zij3)=pij3(sxij-l/2,syij-w/2,sz)\\ pij4(xij4,yij4,zij4)=pij4(sxij+l/2,syij-w/2,sz)\end{array}\right.$

Wherein, the position number of i and j respectively tof depth camera x direction and the motion of y direction in x/y plane, i=1,2, 3 ... ..., j=1,2,3 ... ...；pij1(xij1,yij1,zij1)、pij2(xij2,yij2,zij2)、pij3(xij3, Yij3, zij3), pij4 (xij4, yij4, zij4) be respectively cubic objects top surface four angle points in space coordinates oxyz Under coordinate；The precise displacement that sxij moves in x direction for x direction motion translation platform；Syij is y direction motion translation platform in y The precise displacement of direction motion；The precise displacement that sz moves in z direction for z direction motion translation platform；L and w is respectively cube The length and width of target；

(5) tof depth camera carries out three-dimensional measurement to cubic objects, obtains four corner location of cubic objects top surface Three-dimensional measurement coordinate figure is it may be assumed that four angle points coordinate under tof depth camera three-dimensional measurement coordinate system ocxcyczc is respectively as follows: pij1’(xij1’,yij1’,zij1’)、pij2’(xij2’,yij2’,zij2’)、pij3’(xij3’,yij3’,zij3’)、 pij4’(xij4’,yij4’,zij4’)；

(6) travel through whole x/y plane, obtain the locus of cubic objects angle point at all of xy position at this z direction position With three-dimensional coordinate measurement value；Bring in above-mentioned three-dimensional coordinate transformational relation, solution system of linear equations is realized to tof depth camera The demarcation of three-dimensional coordinate.